Data backup device and method for use with a computer, and computer-readable recording medium having data backup program recorded thereon

ABSTRACT

A technique related to a data backup for a computer. There are provided a selection section, an archive file creation section, and a backup processing section. The selection section selects data files satisfying given conditions from among data files stored in a first storage section. The archive file creation section creates N (N is a natural number) archive files by grouping the plurality of data files selected by the selection section and which repeats the archive file creation processing M (M is a natural number) times. The backup processing section stores the archive files created by the archive file creation section into a second storage section. The technique enables efficient copying of a data file in a short period of time.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a data backup device and methodsuitable for use with a computer and to a computer-readable recordingmedium having a data backup program recorded thereon.

(2) Description of the Related Art

In recent years, computers, such as personal computers, as well ascomputer networks dominantly comprising Internet and personal computercommunication, have become prevalent. In association with this tendency,important data sets such as electronic mail or documents stored in astorage device of a computer have also increased.

The contents of the important data sets may be destroyed or becomeunavailable by the user's faulty operation of the computer or by abreakdown in the storage device. The loss of data results in significantdamage in terms of time and money.

In a method of minimizing damage by immediately recovering a data filein the event of problems such as the loss of data, a technique ofduplicating information (i.e., a data backup technique) becomesimportant.

As shown in FIG. 18, a computer 50 comprises a predetermined storagedevice 51 and a backup storage device 52. Data which are identical tothe data stored in the storage device 51 are stored in the storagedevice 52, thereby preventing the foregoing damage.

With regard to common data backup methods, there are various data backupmethods which vary among the types of data files to be reproduced (orcopied) and the ways the data files are input or output. Each of themethods will now be described.

(a) Data backup methods varying with the types of data files to becopied

These data backup methods are classified into three methods according tothe type of data file to be copied; that is, a full backup method, adifferential backup method, and an incremental backup method.

(a1) Full Backup Method

According to this method, all the data files stored in an area instorage to be copied are copied at one time.

(a2) Differential Backup Method

According to this method, among the data files stored in an area instorage to be copied, the data files copied are those whose data havebeen updated or which have been newly created since the last backupversion was created by full backup.

(a3) Incremental Backup Method

According to this method, among the data files stored in an area instorage to be copied, only the data file copied are those whose datahave been updated or which has been newly created since the last backupversion was created by full backup or differential backup.

(b) Data backup methods varying with the ways a data file is input oroutput

The processing time required for the data backup method is determined bya method of inputting or outputting a data file required when the datafile is copied. The inputting and outputting of one data file involvesopen processing, read/write processing, and close processing. Withreference to FIG. 19, an explanation will be given of copying of a fileA stored in the storage device 51 (for holding the original file) to afile A′ stored in the storage device 52 (for holding a copied file).

More specifically, the open processing is a process for making a datafile available by extraction of information about the data file; e.g.,the location of the data file in the storage device, the date on whichthe file was created, or the size of the data file.

The read/write processing is a process for reading contents from or intoa data file and is designed to write the data read from the file A tothe file A′. The close processing is a process for terminatingutilization of a data file and is designed to discard information aboutthe data file extracted at the time of open processing.

The following explanation describes the three types of data backupmethods that vary with the file input-output processing methods.

(b1) Data Backup Method Utilizing Disk Image

Under this method, data are directly read from the storage device andwritten on another storage device without regard to a data structureconfigured in the storage device. For example, as shown in FIG. 20, rawdata stored in the storage device 51 are stored in the storage device52, exactly as they are.

Since this method disregards the data structure configured in thestorage device, there is no need to execute open/close processing forthe purpose of inputting or outputting data on a file-by-file basis,thus resulting in a reduction in processing time.

(b2) Data Backup Method Utilizing File Image (1)

Under this method, data are read on a file-by-file basis, and thethus-read data are written into another storage device on a file-by-filebasis according to the data structure configured in the storage device.For example, as shown in FIG. 21, data concerning files A, B, and Cstored in the storage device 51 are stored, respectively, in the storagedevice 52 on a file-by-file basis.

In short, this method enables data to be copied or restored on afile-by-file basis according to the data structure configured in thestorage device and can be applied to the foregoing differential orincremental backup method.

(b3) Data Backup Method Utilizing File Image (2)

Under this method, data are read on a file-by-file basis according tothe data structure configured in the storage device, and the thus-readdata files are grouped into one data file. The data files are writteninto another storage device on a file-by-file basis. For example, asshown in FIG. 22, all the data sets concerning the files A, B, and Cstored in the storage device 51 are collectively stored in the storagedevice 52.

This method enables data to be copied or restored on a file-by-filebasis according to the data structure configured in the storage device.Further, since this method permits the data files read from the storagedevice 51 to be grouped into one data file and to be written into thestorage device 52, execution of the open and close processing isrequired to be performed only once, collectively, in order to write thedata files into the storage device 52.

More specifically, many commercially-available data backup softwarepackages employ the foregoing method (b2). For example, a backupsoftware package bundled with MS-Windows 95, which is commerciallyavailable from Microsoft Co., Ltd. and is an operating system (OS) foruse in a personal computer, employs the data backup method (b2). Inaddition, ASCserver and Cheyenne Backup, which are available fromComputer Associates Ltd., and Seagate Backup, which is available fromSeagate Co., Ltd., also employ the foregoing method (b2).

In a case where user data comprising electronic mail or documents arecopied in a personal computer which uses a 32-bit Pentium microprocessorof 90 MHz, through use of the backup software package bundled withMS-Windows 95, the processing rate determined from the processing timerequired to copy the data by measurement is 185 KB/s.

The foregoing data backup methods suffer the following problems. First,as mentioned previously in section (a) entitled “Data backup methodsvarying with the types of data files to be copied,” under thedifferential or incremental backup method, if data are copied severaltimes, there are required recording mediums having backup operations orbackup data files recorded thereon in the number corresponding to thenumber of times the data are copied, resulting in an increase in thenumber of recording mediums. Further, in this case, when the copied datafiles are restored, they must be restored in the order in which theywere copied.

To solve the foregoing problem, the number of backup data files orrecording mediums must be reduced, and the copied data files must berestored in a simple manner. Accordingly, all the data files must becopied after the differential or incremental backup operation has beenperformed for a given period of time. In order to reduce the overallprocessing time required by a data backup system, the processing timerequired for the full backup operation must be reduced.

Next, in the case of data backup method (b1) utilizing a disk imagedescribed in section (b) entitled “Data backup methods varying with theways a data file is input or output,” since the data structure isdisregarded, data cannot be copied on a file-by-file basis, which inturn makes it impossible to perform the differential or incrementalbackup operation. Further, the method involves reading of a null dataset from an empty area in the storage device 51 and writing of thethus-read null data set to the other storage device 52, causing waste ofresources.

In the case of data backup method (1) utilizing a file image referred toin section (b2), each of the storage device 51 (holding the originalfile) and the storage device 52 (holding a copied file) must open andclose a data file on a file-by-file basis, requiring a longer processingtime as compared with that required by method (b1).

In the case of data backup method (2) utilizing a file image referred toin section (b3), a data file is opened and closed once for each datafile. Therefore, the processing time required by method (b3) can bereduced in comparison with that required by method (b2), but stillremains longer than that required by method (b1).

SUMMARY OF THE INVENTION

The present invention has been contrived in view of the foregoingdrawbacks in the art, and an object of the present invention is toprovide a data backup device and method for use with a computer thatenables efficient copying of a data file in a short period of time bymaking improvements in a data file to be copied.

Another object of the present invention is to provide acomputer-readable recording medium having a data backup program for thepurpose of performing the foregoing data backup operation recordedthereon.

To these ends, according to one aspect of the present invention, thereis provided a data backup device for use with a computer which storesdata files stored in a first storage section into a second storagesection in a duplicated manner, the device comprising: a selectionsection for selecting data files satisfying given conditions from amongthe data files stored in the first storage section; an archive filecreation section which creates N (N is a natural number) archive filesby grouping the plurality of data files selected by the selectionsection and which repeats the archive file creation processing M (M is anatural number) times; and a backup processing section which stores thearchive files created by the archive file creation section into thesecond storage section.

Since the data backup device according to the present invention groupsthe data files to be copied into archive files before the data files arecopied, the time required to copy the data files can be reduced. Hence,the present invention yields the advantage of enabling significantimprovements in the processing capability of the data backup device.Further, since the data backup device uses distributed processing tocause the archive file creation section to create an archive file and tocause the backup processing section to copy the thus-created archivefile, the processing operations can be performed speedily andaccurately, thus increasing the processing rate of the data backupdevice.

Preferably, in the data backup device according to the presentinvention, the selection section is configured to select a data file ofa given size or smaller.

Since the data backup device according to the present invention isconfigured in such a way that the selection section selects a data fileof a given size or smaller, the processing time and the size of thearchive file to be stored can be limited. Accordingly, the storagecapacity of the first storage section can be reduced.

Preferably, in the data backup device according to the presentinvention, the selection section is configured in such a way that whenthe archive file creation section is performing the m^(th) operation(where “m” is a natural number satisfying m≦M), the selection sectionselects only those data files which have been modified or newly createdsince the archive file creation section performed the M−1^(th)operation.

Since the data backup device according to the present invention isconfigured in such a way that the selection section selects only thosedata files which have been modified or newly created since the archivefile creation section created an archive file in the precedingprocessing, the number of data files to be grouped can be reduced, andthe number of archive files can also be reduced. In this case, thebackup processing rate of the data backup device can be increased.

Preferably, in the data backup device according to the presentinvention, the selection section is configured in such a way that whenthe archive file creation section is performing the m^(th) operation(where m≦M), the selection section selects only those data files whichhave been modified or newly created since the archive file creationsection performed the first operation.

Since the data backup device according to the present invention isconfigured in such a way that, in a case where the number of archivefiles is increased, the selection section extracts the archive filescreated when the archive file creation section has performed the firstoperation and selects only the data files which have been modified ornewly created since the archive file creation section performed thefirst operation, the number of data files to be grouped can be reduced.In this case, the number of archive files can be reduced.

Preferably, in the data backup device according to the presentinvention, the archive file creation section is configured in such a waythat, after having created an archive file, the archive file creationsection compresses the thus-created archive file.

Since the data backup device according to the present invention isconfigured so as to compress the created archive file, the size (amountof data) of the archive file to be stored can be reduced. The presentinvention yields the advantage of being able to reduce storage capacityof the first storage section for creating archive files or that of thesecond storage section for storing copied archive files or data files.

Preferably, in the data backup device according to the presentinvention, the archive file creation section is configured in such a waythat, after having compressed each of data files, the archive filecreation section creates archive files.

Since the data backup device according to the present invention isconfigured so as to create archive files after having compressed each ofdata files to be copied, data files can be newly added to the archivefiles without decoding the archive files, whereby archive files cancreated speedily.

Preferably, in the data backup device according to the presentinvention, the archive file creation section is configured in such a waythat the archive file creation section adds the data file selected bythe selection section during the m^(th) operation (where m≦M) of thearchive file creation section to the archive files created during them−1^(th) operation of the same.

Since the data backup device according to the present invention isconfigured so as to add the data file to be newly updated to the archivefile that has been created in the preceding grouping operation, thepresent invention yields the advantage of being able to create archivefiles by an extremely simple operation; that is, by addition of a datafile to archive files.

Preferably, in the data backup device according to the presentinvention, the archive file creation section is configured in such a waythat, after having deleted a past data file corresponding to a data fileto be updated from the archive files, the archive file creation sectionadds the data file selected by the selection section during the m^(th)operation (where m≦M) of the archive file creation section to thearchive files created during the m−1^(th) operation of the same.

Since the data backup device according to the present invention isconfigured so as to delete a data file corresponding to a data file tobe updated when a data file to be newly updated is added to the archivefile that has been created in the preceding grouping operation, theamount of storage of the archive files can be reduced, and only thenewest information can be copied to the second storage section.

Preferably, in the data backup device according to the presentinvention, the backup processing section is configured to store into thesecond storage section the archive files and those data files that havefailed to satisfy given conditions.

Since the data backup device according to the present invention isconfigured so as to group data files to be copied into archive filesbefore the data files are copied, the present invention yields theadvantages of being able to reduce the time required to copy the datafiles and being able to significantly improve the processing capabilityof the data backup device. Further, since the data backup device usesdistributing processing in performing the creation of an archive file inthe archive file creation section and in copying the thus-createdarchive files in the backup processing section, the processingoperations can be perform speedily and accurately, thereby increasingthe processing rate of the data backup device.

Preferably, in the data backup device according to the presentinvention, the backup processing section is configured to compress thearchive files and those data files that have failed to satisfy givenconditions and then store the thus-compressed files into the secondstorage section.

Since the data backup device according to the present invention isconfigured so as to compress the archive files and the data files thathave failed to satisfy given conditions when these files are copied tothe second storage section, the present invention yields the advantagesof being able to reduce the load exerted on the archive file creationsection when the archive file creation section repeatedly createsarchive files and being able to reduce the storage capacity of thesecond storage section to which the data files are copied.

Preferably, in the data backup device according to the presentinvention, the backup processing section is configured in such a waythat, after having added to the archive files, another archive file orthose data files that have failed to satisfy given conditions, thebackup processing section stores the archive files into the secondstorage section.

Since the data backup device according to the present invention isconfigured so as to copy the archive files after the addition to thearchive files or another archive file or those data files that havefailed to satisfy given conditions, the number of files to be copied canbe reduced. In this case, the present invention yields the advantage ofbeing able to improve the copying capability of the data backup device.

Preferably, in the data backup device according to the presentinvention, the backup processing section is configured in such a waythat, after having grouped into another archive file the archive filesand those data files that have failed to satisfy given conditions, thebackup processing section stores the thus-grouped archive files into thesecond storage section.

Since the data backup device according to the present invention isconfigured so as to copy the archive files and those data files thathave failed to satisfy given conditions after these files have beengrouped into another archive file, the user can speedily extract data ona per-unit basis easily available for the user.

Preferably, in the data backup device according to the presentinvention, the backup processing section is configured in such a waythat the backup processing section causes the archive file creationsection to create an archive file one time immediately before copying tothe second storage section the archive files and those data files thathave failed to satisfy given conditions.

Since the data backup device according to the present invention isconfigured in such a way as to allow the archive file creation sectionto create an archive file one time immediately before the archive filesand those data files that have failed to satisfy given conditions arecopied to the second storage section, the newest data file can be copiedwithout fail, contributing to improvements in the performance of thedata backup device.

According to another aspect of the present invention, there is provideda data backup method for use with a computer which stores the data filesstored in a first storage section into a second storage section in aduplicated manner, the method comprising the steps of: selecting datafiles that satisfy given conditions from among the data files stored inthe first storage section; creating N (N is a natural number) archivefiles by grouping the plurality of selected data files; and storing thearchive files into the second storage section after having repeatedlyperformed the data file selection and the archive file creation M (M isa natural number) times.

Since the data files to be copied are grouped into archives before thedata files are copied under the data backup method according to thepresent invention, the time required to copy the data files can bereduced. Hence, the present invention yields the advantage of being ableto significantly improve the processing capability of a data backupdevice. Further, under this method, since distributed processing is usedto cause the archive file creation section to create an archive file andto cause the backup processing section to copy the thus-created archivefile, the processing operations can be performed speedily andaccurately, thus increasing the processing rate of the data backupdevice.

According to still another aspect of the present invention, there isprovided a computer-readable recording medium on which is recorded adata backup program for activating a computer in order to store the datafiles stored in a first storage section into a second storage section ina duplicated manner, the program comprising: a selection function ofselecting from among the data files stored in the first storage sectionthose data files that satisfy given conditions; an archive file creationfunction of creating N (N is a natural number) archive files by groupingthe plurality of selected data files and repeating the archive filecreation processing M (M is a natural number) times; and a backupprocessing function of storing the thus-created archive files into thesecond storage section.

Since, before being copied, the data files to be copied are grouped intoarchives by means of the computer-readable recording medium having adata backup program recorded thereon according to the present invention,the time required to copy the data files can be reduced. Hence, thepresent invention yields the advantage of being able to significantlyimprove the processing capability of a data backup device. Further,under this method, since distributed processing is used to cause thearchive file creation section to create an archive file and to cause thebackup processing section to copy the thus-created archive file, theprocessing operations can be performed speedily and accurately, thusincreasing the processing rate of the data backup device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the configuration of a data backupdevice for use with a computer according to an embodiment of the presentinvention;

FIG. 2 is a table showing one example of a database created by the databackup device according to the embodiment;

FIG. 3 is a flowchart for explaining the operation of the data backupdevice according to the embodiment;

FIG. 4 is a schematic representation for explaining the operation of thedata backup device according to the embodiment;

FIG. 5 is a schematic representation for explaining an archive filecreation operation performed by an archive file creation sectionaccording to the embodiment;

FIG. 6 is a schematic representation for explaining the archive filecreation operation performed by the archive file creation sectionaccording to the embodiment;

FIG. 7 is a flowchart for explaining the archive file creation operationperformed by the archive file creation section according to theembodiment;

FIG. 8 is a schematic representation for explaining the archive filecreation operation performed by the archive file creation sectionaccording to the embodiment;

FIG. 9 is a flowchart for explaining the archive file creation operationperformed by the archive file creation section according to theembodiment;

FIG. 10 is a schematic representation for explaining the archive filecreation operation performed by the archive file creation sectionaccording to the embodiment;

FIG. 11 is a schematic representation for explaining a backup operationperformed by the backup processing section according to the embodiment;

FIG. 12 is a flowchart for explaining the backup operation performed bythe backup processing section according to the embodiment;

FIG. 13 is a schematic representation for explaining a backup operationperformed by the backup processing section according to the embodiment;

FIG. 14 is a flowchart for explaining the backup operation performed bythe backup processing section according to the embodiment;

FIG. 15 is a schematic representation for explaining a backup operationperformed by the backup processing section according to the embodiment;

FIG. 16 is a flowchart for explaining the backup operation performed bythe backup processing section according to the embodiment;

FIG. 17 is a schematic representation for explaining a backup operationperformed by the backup processing section according to the embodiment;

FIG. 18 is a schematic representation for explaining a popular backupoperation;

FIG. 19 is a schematic representation for explaining another popularbackup operation;

FIG. 20 is a schematic representation for explaining a backup methodwhich utilizes disk images;

FIG. 21 is a schematic representation for explaining a backup methodwhich utilizes file images; and

FIG. 22 is a schematic representation for explaining another backupmethod which utilizes file images.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(a) Description of Embodiment of the Present Invention

With reference to the accompanying drawings, an embodiment of thepresent invention will be described.

FIG. 1 is a block diagram showing the configuration of a data backupdevice for use with a computer according to one embodiment of thepresent invention. A data backup device 40 for use with a computer shownin FIG. 1 comprises a computer 1, a first storage section (memory A) 20,and a second storage section (memory B) 30. Data files stored in thefirst storage section 20 are stored in the second storage section 30 ina duplicated manner. Memory devices A, B are configured in the form ofexternal storage devices such as hard disks.

More specifically, the computer 1 comprises a CPU (Central ProcessingUnit) 10, memory devices 11 a, 11 b, a display 12, and a keyboard 13.The memory devices 11 a, 11 b are connected to the CPU 10 by way of abus 14, whereas the display 12 and the keyboard 13 are connected to theCPU 10 by way of the bus 14 and the input-output interfaces (I/O) 15 c,15 d. The first storage section 20 and the second storage section 30 areconnected to the CPU 10 by way of the bus 14 and input-output interfaces(I/O) 15 a, 15 b.

The CPU 10 controls individual sections provided in the computer 1 andthe first and second storage sections 20, 30 provided outside thecomputer 1. To this end, as shown in FIG. 1, the CPU 10 is configured tocomprise a selection section 101, an archive file creation section 102,and a backup processing section 103. The CPU 10 operates according to abackup program recorded in the memory device 11 a, which will bedescribed later. The foregoing sections will be individually describedin detail later.

The memory device lla stores a backup program for implementing therespective functions of the selection section 101, the archive filecreation section 102, and the backup processing section 103 and employs,e.g., RAM or ROM. In short, according to the backup program stored inthe memory device 11 a, the CPU 10 is activated to implement variousfunctions of the backup device according to the present embodiment.

The backup program is stored in the memory device 11 a by installationof the backup program recorded on a recording medium such as a floppydisk.

The memory device 11 b is a working memory device used for arithmeticoperations of the computer 1 b and employs, e.g., RAM. Further, thedisplay 12 is an image display means for displaying data to be computedby the computer 1 and the result of computation of the data performed bythe computer 1. The keyboard 13 is a means for entering keys used forarithmetic operations of the computer 1.

The selection section 101 of the CPU 10 selects from the data filesstored in the first storage section 20 those data files that satisfygiven conditions. More specifically, the selection section 101 retrievesdata sets, such as the name of a data file, the date on which a datafile was created, and the size of data, from all the data files storedin the area of the first storage section 20 to be copied. From thethus-retrieved data sets, the selection section 101 selects data filesthat satisfy given conditions.

The selection section 101 classifies the thus-selected data filesaccording to specifiable information (e.g., the name of a data file),thereby creating a database such as that shown in FIG. 2.

As mentioned previously, the selection section 101 can select all thedata files to be grouped, and the archive file creation section 102,which will be described later, can group all the thus-selected datafiles into an archive file. Accordingly, there can be minimized thenumber of times the data file is opened and closed when the backupprocessing section 103, which will be described later, performs a backupoperation.

More specifically, since the number of times the data file is opened andclosed is proportional to the number of data files to be copied, thenumber of times a data filed is opened and closed can be reduced byreduction of the number of data files.

The operating system (OS) of the computer 1 can define the foregoingarea to be copied in partitions logically formed in the first storagesection 20 or in directories of a file system having a hierarchicalstructure.

The selection section 101 is designed to select data files of smallerthan a given size. More specifically, the backup processing rate isdecreased primarily for reasons of handling a plurality of small datafiles. If data files of smaller than a given size are grouped together,the processing time can be reduced. Further, since the size of anarchive file can be limited, the storage capacity of the first storagesection 20 can be reduced.

The selection section 101 is designed so as to select only those datafiles that has been modified or newly created since the archive filecreation section 102 performed the m−1^(th) operation when the archivefile creation section 102, which will be described later, is performingthe m^(th) operation (m is a natural number satisfying m≦M).

Since the selection section 101 selects only the new data file that hasbeen processed during the preceding operation cycle of the archive filecreation section 102, the number of data files to be grouped can bereduced. Further, the number of archive files can also be reduced. Thisprocessing corresponds to the incremental backup processing mentionedpreviously.

The selection section 101 is designed to select only those data filesthat have been modified or newly created since the archive file creationsection 102 performed the first operation when the archive file creationsection 102 is performing the m^(th) operation (m≦M).

If the size (capacity) of the archive file or the number of archivefiles has been increased as a result of the archive file creationsection 102 to be described later grouping the data files several times,the data files can be grouped again by extracting only those data filesthat have been modified or newly created since the archive file creationsection 102 performed the first operation. Accordingly, the number ofdata files to be grouped can be reduced. Even in this case, the numberof archive files can be reduced. The foregoing processing corresponds tothe differential backup processing mentioned previously.

The archive file creation section 102 shown in FIG. 1 creates N archivefiles (N is a natural number) by grouping the plurality of data filesselected by the selection section 101 and repeats the archive filecreation processing M times (M is a natural number). The expression“archive file” used herein refers to a file into which a plurality ofdata files are grouped.

First, the archive file creation section 102 opens the data filescontained in the list of a database created in the selection section 101and reads the contents from the data files. The archive file creationsection 102 then groups the thus-read data files into one archive file.

The number N (N is a natural number) of archive files can be determinedon the basis of the predetermined size or number of archive files or onthe basis of the number of directories in the area to be copied.

After having grouped the data files into the archive file, the archivefile creation section 102 creates an archive file database whichincludes the names of data files and the dates on which the data fileswere created. The thus-created archive file database is stored in thefirst storage section 20 together with the archive file. At this time,the thus-created archive file database may be included so as toconstitute a part of the archive file or stored as another data file.

All the data files included in the initially-created database (i.e., thedatabase described with reference to FIG. 2) are to be subjected to theforegoing processing. As shown in FIG. 2, the thus-processed data filesare recorded as having been processed (e.g., the data files are assignedan “already-grouped” sign).

As mentioned previously, as a result of grouping the plurality of datafiles to be copied into one file before the files are copied, the numberof files to be copied to the second storage section 30 can besignificantly reduced. Further, the number of times the data files areopened or closed at the time of backup processing can be reduced.

In short, it becomes possible to realize backup processing having theadvantage of the disk image backup method; that is, the advantage ofbeing able to reduce the processing time, as well as the advantage ofthe file image backup method; that is, the advantage of being able tocopy or restore a data file on a file-by-file basis.

Further, the archive file creation section 102 is designed to repeatedlyperform a round of foregoing grouping operations M times. The number (M)of times the grouping operation is repeated is determined on the basisof the predetermined time interval between the grouping operations andthe number of times of the processing therefor.

More specifically, since the archive file creation section 102 does notcopy the data files grouped one time to the second storage section 30but groups the data files M times, optimum information can beefficiently copied to the storage section.

In other words, the newest pieces of information relating to the datafiles to be copied are grouped under given conditions (e.g., the timeinterval between grouping operations or the number of times the groupingoperation is performed). Therefore, the load (i.e., the number of datafiles to be processed) required by the archive file creation section togroup the data files one time can be reduced, and the load can bedispersed among the individual sections of the computer.

Even in a case where a correction, such as addition or deletion of adata set occurred during a short period of time, is made to a data file,only the archive file including the data set is extracted from the Narchive files grouped M times and can be amended.

The foregoing archive file creation section 102 is designed to create anarchive file and compresses the thus-created archive file. In general,as the size of a data file to be compressed becomes larger, acompression ratio at which the data file is compressed becomes greater.For this reason, a higher compression ratio is liable to be achieved bycompressing the individual data files than archive files.

The foregoing archive file creation section 102 creates an archive fileafter having compressed each of data files. As a result, when a datafile is added to the archive file, the data file can be added to thearchive file without the need of decoding the archive file.

The foregoing archive file creation section 102 is designed to add thedata file selected by the selection section 101 during the m^(th) (wherem≦M) operation of the archive file creation section 102 to the archivefile created during the M−1^(th) operation of the same.

More specifically, as mentioned previously, the archive file creationsection 102 is designed to create an archive file and to store thethus-created archive file in the first storage section 20 together withthe archive file database. In this example, the archive file creationsection 102 is designed to perform the creation of an archive file Mtimes without use of means for storing data to the first storage section20.

In short, a data file which is newly created when the data files aregrouped by the m^(th) operation of the archive file creation section 102is added to the archive file created by the m−1^(th) operation of thesame. At this time, information about the newly updated m^(th) data fileis added to the archive data base.

When the m^(th) data file is added to the archive database, a decisionis made through retrieval as to whether or not there is an informationitem relating to a data file corresponding to the m^(th) data file isstored in the m−1^(th) data file. If the information item is stored inthe m−1^(th) archive file data base, a marking (or a check mark, e.g.,“OLD”) which represents that the thus-retrieved information item is anexisting data file corresponding to the m^(th) data file is assigned tothe information item. When a new data file is added to the archive filedatabase, the data file may be added not only to the tail end of thedatabase but also to the leading end of the database.

The foregoing archive file creation section 102 is arranged to deletefrom the archive file a past data file corresponding to the data fileselected by the selection section 101 during the m^(th) (m≦M) operationand to add the thus-selected data file to the archive file createdduring the m−1^(th) operation of the archive file creation section 102.Even in this case, as mentioned previously, the archive file creationsection 102 performs the creation of an archive file M times without useof the means for storing data to the first storage section 20.

More specifically, when a data file newly updated during the m^(th)grouping operation of the archive file creation section 102 is added tothe archive file created during the m−1^(th) grouping operation of thesame, the data file—which is stored in the archive file created duringthe m−1^(th) grouping operation and corresponds to the data file to beupdated—is deleted to thereby reduce the size of the archive file. Whenthe data file is added to the archive file, the data file may be addedto the leading end of the archive file in the manner analogous to thatmentioned previously.

Next, the backup processing section 103 shown in FIG. 1 stores thearchive file created by the archive file creation section 102 into thesecond storage section 30. More specifically, the backup processingsection 103 is designed to respectively store (i.e., copy) the datafiles failed to satisfy given conditions and the archive file. The datafiles grouped into the first storage section 20 may be deleted afterhaving been stored in the second storage section 30.

The backup processing section 103 compresses respectively the data filesfailed to satisfy given conditions and the archive files and store thethus-compressed files into the second storage section 30.

Specifically, in the processing stage, which precedes a copying stageand in which the creation of an archive file is repeated M times, thebackup processing section 103 does not compress the archive files andthe data files failed to satisfy given conditions. In contras, whencopying the files to the second storage section 30, the backupprocessing section 103 compresses the files, whereby the load which isexerted on the backup processing section 103 when the backup processingsection 103 compresses files can be reduced during the repeated creationof an archive file.

Further, the foregoing backup processing section 103 is designed to addto the archive another archive file or those data files that have failedto satisfy given conditions and to store the archive file into thesecond storage section 30. More specifically, addition to one of thepreviously-created archive files the data file that has failed tosatisfy given conditions enables a reduction in the number of data filesto be copied to the second storage section 30.

Although the backup processing section 103 is designed to add to any oneof the N archive files the data file that has failed to satisfy givenconditions, the backup processing section 103 is not limited to such anoperation but may create a new archive file by grouping only those datafiles that have failed to satisfy given conditions. In other words, thenumber of archive files is not limited to N.

Further, the second storage section 30 may add to the archive file thosedata files that have failed to satisfy given conditions after the datafiles and the archive file have been respectively copied to the secondstorage section 30.

The backup processing section 103 is designed to copy to the secondstorage section 30 the data files that have failed to satisfy givenconditions and the archive files after having grouped these files intoanother archive file. In short, the archive files that have beencollected in groups easily available for the user, such as a directory,can be further grouped together so as to be distinguished from otherdata files.

Although the backup processing section 103 is designed to group intoanother archive file the archive files and those data files that havefailed to satisfy given conditions, the backup processing section 103may create another new archive file by further grouping a plurality ofonly archive files.

In this case, the number of archive files is not limited to N, namely,the archive files can be collected into groups easily available for theuser, such as a directory, and the number of data files to be copied tothe second storage section 30 can also be reduced.

The backup processing section 103 is designed to cause the archive filecreation section 102 to again create archive files one time immediatelybefore respectively storing those data files that have failed to satisfygiven condition and the archive files into the second storage section30.

During the interval from when the archive file creation section 102 hasperformed grouping operations M times to when the backup processingsection 103 copies data to the second storage section, the backupprocessing section 103 can copy all those data files that have beennewly created or modified without fail.

As mentioned previously, since the data backup device 40 usesdistributed processing to cause the foregoing archive file creationsection 102 to create an archive file and to cause the backup processingsection 103 to copy the thus-created archive file, the processingoperations can be performed speedily and accurately.

With reference to FIGS. 3 and 4, an explanation will be given of theoperation of the data backup device 40 for use with a computer accordingto one embodiment of the present invention having the foregoingconfiguration.

First, the selection section 101 of the computer 1 shown in FIG. 1determines an area to be copied among the data sets stored in the firststorage section 20 (step a1 show in FIG. 3). Pieces of informationrelating to the names of files, the dates on which the files werecreated, and the size of the files are fetched through retrieval of datafiles stored in the thus-determined area (step a2 shown in FIG. 3).

Subsequently, data files that satisfy given conditions are selected fromamong the thus-retrieved data files, and there is created a databaserelating to those data files that satisfy given conditions such as thoseshown in FIG. 2 (step a3 shown in FIG. 3).

The archive file creation section 102 opens data files included in thelist of data base created by the selection section 101 (step a4 shown inFIG. 3) and reads the contents of those data files (step a5 shown inFIG. 3). The selected data files may be opened in order or at one time.

Subsequently, the thus-read data files are grouped into one of N archivefiles (step a6 shown in FIG. 3 and step {circle around (1)} shown inFIG. 4). In the case of an example shown in FIG. 4, data files A, B, andD are grouped into one archive file.

The archive file creation section 102 creates an archive file databaseincluding the names of the thus-grouped data files and the dates onwhich the data files were created (step a7 shown in FIG. 3), storing thethus-created database to the first storage section 20 together with thearchive file.

A decision is made as to whether or not all those data files that areincluded in the database created by the selection section 101 have beenread (step a8 shown in FIG. 3). If those data files have not yet beenread (NO in step a8 shown in FIG. 3), the data files that are includedin the database created by the selection section 101 are again opened(step a4 shown in FIG. 3). Processing analogous to that mentionedpreviously will be carried out hereafter.

In contrast, if all those data files included in the database created bythe selection section 101 have already been read (YES in step a8 shownin FIG. 3), a decision is made as to whether or not grouping operationshave already been repeatedly performed M times (step a9 shown in FIG.3).

If it is decided in step a9 that the grouping operations have not yetbeen repeatedly performed M times (NO in step a9 shown in FIG. 3), theselection section 101 creates once again a database relating to onlythose data files that satisfy given conditions (step a3 shown in FIG.3).

In contrast, if the grouping operations have already been repeatedlyperformed (YES in step a9 shown in FIG. 3), grouped N archive files andthose data files that have failed to satisfy given condition arerespectively copied to the second storage section 30 (step a10 shown inFIG. 3, and step {circle around (2)} shown in FIG. 4). In the case ofthe example shown in FIG. 4, one archive file and data files C and E arerespectively copied to the second storage section 30.

The operations of the archive file creation section 102 and the backupprocessing section 103 in the foregoing data backup device 40 will bedescribed in detail.

(b) Creation of an Archive File in the Archive File Creation Section 102

(b1) Where an archive file is created and compressed:

With reference to FIG. 5, an explanation will be given of the case wherethe archive file creation section 102 creates an archive file bygrouping data files and compresses the thus-created archive file.

First, the archive file creation section 102 creates one archive file bygrouping those data files that satisfy given conditions (e.g., datafiles A, B, and D) (step sl shown in FIG. 5) and compresses thethus-created archive file (step s2 shown in FIG. 5).

As mentioned previously, the foregoing data backup device 40 is capableof reducing the size (or amount of data) of the archive file, thusyielding the advantage of being able to reduce the storage capacity ofthe first storage section 20 that creates an archive file, as well as ofthe second storage section 30 that stores the archive files and the datafiles.

(b2) Where an archive file is created by compression of data files to becopied

With reference to FIG. 6, an explanation will be given of a case wherethe archive file creation section 102 creates an archive file afterhaving compressed a plurality of data files.

First, the archive file creation section 102 compresses those data filesthat satisfy given conditions (e.g., data files A, B, and D) (step s3shown in FIG. 6) and creates one archive file by grouping together theplurality of thus-compressed data files (step s4 shown in FIG. 6).

Accordingly, when data files are added to the archive file, data filescan be added to the archive file without the need of decoding thearchive file, thus enabling speedy creation of an archive file.

(b3) Where data files are added to the archive file that has beencreated in the preceding grouping operation

With reference to FIGS. 7 and 8, an explanation will be given of a casewhere data files are added to the archive file that has been created bythe preceding grouping operation.

First, when the archive file creation section 102 performs the m^(th)grouping operation, the selection section 101 selects a data file to becopied (step b1 shown in FIG. 7, and step b10 shown in FIG. 8). Inresponse to the selection of the data file, the archive file creationsection 102 determines whether or not a data file corresponding to thedata file selected during the m^(th) grouping operation (i.e., a newdata file B) is included in the database relating to the archive filecreated by the m−1^(th) grouping operation (step b2 shown in FIG. 7).

If it is decided in step b2 that the corresponding data file is includedin the database (YES in step b2 shown in FIG. 7), a marking (e.g., OLD)representing that this file is an existing data file is appended to thecorresponding data file (step b3 shown in FIG. 7, and step bll shown inFIG. 8). The data file selected during the m^(th) grouping operation isadded to the archive file created by the m−1^(th) grouping operation(step b4 shown in FIG. 7, and step b12 shown in FIG. 12).

Subsequently, pieces of information relating to the thus-added m^(th)data file (e.g., the name of the data file, the date on which the datafile was created, or the size of the data file) are added to thedatabase relating to the m−1^(th) archive file (step b5 shown in FIG. 7,and step b13 shown in FIG. 8).

In contrast, if it is determined in step b2 shown in FIG. 7 that thereis no corresponding data file (NO in step b2 shown in FIG. 7), the datafile is added to the m−1^(th) archive file, as is (step b4 shown in FIG.7, and step b12 shown in FIG. 8). Information relating to the thus-addeddata file is added to the data base of the m−1^(th) archive file (stepb5 shown in FIG. 7, and step b13 shown in FIG. 8).

As mention ed previously, the foregoing data backup device 40 isconfigured to add the data file to be newly updated to the archive filethat has been created by the preceding operation of the archive filecreation section 102, yielding the advantage of being able to create anarchive file through considerably simple processing such as simpleaddition of a data file to an archive file.

(b4) Where a data file is added to the archive file that has beenproduced by the preceding grouping operation after a corresponding datafile has been deleted

With reference to FIGS. 9 and 10, an explanation will be given of a casewhere a data file is added to the archive file that has been created bythe preceding grouping operation after a corresponding file has beendeleted.

With regard to the m^(th) operation of the archive file creation section102, the processing operations performed in steps c1, c2 shown in FIG. 9and step c10 shown in FIG. 10 are analogous with those performed inpreviously-mentioned steps b1, b2 shown in FIG. 7 and step b10 shown inFIG. 8.

If a data file corresponding to the data file selected during the m^(th)operation of the archive file creation section 102 is included in adatabase relating to the archive file created during the m−1^(th)operation of the archive file creation section 102 (YES in step c2 shownin FIG. 9), this data file is deleted from the m−1^(th) archive file(step c3 shown in FIG. 9, and step c11 shown in FIG. 10). Further,information relating to the data file corresponding to the thus-deleteddata file is also removed (or deleted) from the data base relating tothe thus-retrieved m−1^(th) archive file (step c4 shown in FIG. 9, andstep c12 shown in FIG. 10).

Subsequently, the thus-selected data file is added to the archive file(step c5 shown in FIG. 9, and step c13 shown in FIG. 10), and pieces ofinformation relating to the thus-added m^(th) data file (e.g., the nameof the data file, the date on which the data file was created, or thesize of the data file) are added to the database relating to them−1^(th) archive file (step c6 shown in FIG. 9, and step c14 shown inFIG. 10).

In contrast, if it is decided in step c2 shown in FIG. 9 that there isno corresponding data file (NO in step c2 shown in FIG. 9), the datafile is added to the m−1^(th) archive file, as is (step c5 shown in FIG.9, and step c13 shown in FIG. 10). Information relating to thethus-added data file is added to the database relating to the m−1^(th)archive file (step c6 shown in FIG. 9, and step c14 shown in FIG. 10).

As mentioned previously, the data backup device 40 is configured todelete a data file corresponding to a data file to be newly updated whenthe data file to be updated is added to the archive file that has beencreated in the preceding operation of the archive file creation section102, thereby enabling a reduction in the amount of data of the archivefile, as well as the copying of only the newest information to thesecond storage section 30.

(c) Backup Operation of the Backup Processing Section 103

(c1) Where those data files that have failed to satisfy given conditionsand archive files are compressed

In step a9 shown in FIG. 3, when the grouping operation has beenrepeatedly performed M times, the backup processing section 103compresses those data files that have failed to satisfy given conditionsand N archive files and stores the thus-compressed files into the secondstorage section 30 (step d1 shown in FIG. 11). In the case of an exampleshown in FIG. 11, one archive file comprising data files A, B, and D anddata files C and D that have failed to satisfy given conditions arecompressed and are copied to the second storage section 30.

As mentioned previously, the data backup device 40 compresses thearchive file and those data files that have failed to satisfy givenconditions when copying these files to the second storage section 30,thereby yielding the advantages of being able to reduce the load exertedon the data backup device when the creation of an archive file isrepeatedly performed, as well as being able to reduce the storagecapacity of the second storage section 30 to which the data files arecopied.

(c2) Where those data files that have failed to satisfy given conditionsare added to the archive file

Although a detailed explanation has been given of the case where thedata file to be copied is compressed when being copied, an explanationwill be given of a case—where those data files that have failed tosatisfy given conditions are copied after having been added to a createdarchive file—with reference to FIGS. 12 and 13.

First, the backup processing section 103 selects a created archive fileand those data files that have failed to satisfy given conditions (stepe1 shown in FIG. 12) and adds the thus-selected data files that havefailed to satisfy given conditions to the archive file (step e2 shown inFIG. 12).

Subsequently, pieces of information relating to the added data files(e.g., the names of the data files, the dates on which the data fileswere created, or the size of the data file) are added to a databaserelating to the archive file (step e3 shown in FIG. 12, and step e10shown in FIG. 13). The archive file is stored in the second storagesection 30 (step e4 shown in FIG. 12, and step ell shown in FIG. 13).

As mentioned previously, the data backup device 40 adds to the archivefile those data files that have failed to satisfy given conditions andcopies the data files, thereby enabling a reduction in the number offiles to be copied and an improvement in the copying capability of thedata backup device.

(c3) Where another archive file is created by grouping an archive fileand those data files that have failed to satisfy given conditions

Although the explanation has described in detail the case where thosedata files that have failed to satisfy given conditions are added to Narchive files and where the files are copied under the foregoing method,an explanation will be given of a case—where N archive files and thosedata files that have failed to satisfy given conditions are copied aftera new archive file has been formed from these files—with reference toFIGS. 14 and 15.

First, an archive file (handled as e.g., a first archive file) and thosedata files that have failed to satisfy given conditions are selected(step f1 shown in FIG. 14), and a new archive file (handled as e.g., asecond archive file) is formed by grouping the thus-selected firstarchive file and those data files that have failed to satisfy certainconditions (step f2 shown in FIG. 14).

Subsequently, a database relating to the second archive file is formedfrom pieces of information relating to the first archive file (e.g., thename of the archive file, the date on which the file was created, or thesize of the file) and information relating to those data files that havefailed to satisfy given conditions (step f3 shown in FIG. 14, and stepf10 shown in FIG. 15). The thus-newly-created second archive file isstored in the second storage section 30 (step f4 shown in FIG. 14, andstep f11 shown in FIG. 15).

As mentioned previously, the data backup device 40 copies the archivefile and those data files that have failed to satisfy given conditionsafter having grouped these files into another archive file, thusyielding the advantage of being able to extract data in groups easilyavailable for the user.

(c4) Where a grouping operation is again performed immediately beforedata files are copied

With reference to FIGS. 16 and 17, an explanation will be given of acase where the archive file creation section 102 groups data files onceagain immediately before the data files are copied after the archivefile creation section 102 has repeatedly performed the grouping of datafiles M times.

First, the data files selected by the selection section 101 are groupedby the archive file creation section 102 under given conditions, tothereby produce an archive file [step g1 shown in FIG. 16 (or steps a1to a8 shown in FIG. 3) and step g10 shown in FIG. 17].

Subsequently, a decision is made as to whether or not the grouping ofdata files has been repeated M times in step g1 shown in FIG. 16 (stepg2 shown in FIG. 16). If the grouping of data files is not repeated Mtimes (NO in step g2 shown in FIG. 16), the processing performed in stepg1 shown in FIG. 16 is again performed.

In contrast, if the grouping of data files has been performed M times(YES in step g2 shown in FIG. 16), the data files to be copied aregrouped again under given conditions immediately before being copied,thereby updating the contents of data of the archive file created as aresult of grouping of data files M times (step g3 shown in FIG. 16, andstep g11 shown in FIG. 17). The archive file and those data files thathave failed to satisfy given conditions are recorded on the secondstorage section 30 (step g4 shown in FIG. 16, and step g12 shown in FIG.17).

As mentioned previously, the data backup device 40 causes the archivefile creation section 102 to group data files once again immediatelybefore an archive file and data files that have failed to satisfy givenconditions are copied. Therefore, the newest data files can be copiedwithout fail, thereby contributing to improvements in the performance ofthe data backup device 40.

As a result of implementation of the data backup device according to thepresent invention, there can be obtained a data backup processing rateof 335 KB/s—which is about twice as fast as an existing data backup rateof 185 KB/s—under MS-Windows 95. The data backup processing rate wasmeasured under conditions of: selecting data files of smaller than agiven size (45 KB); grouping the thus-selected data files one time(M=1); grouping the data files into one archive file (N=1); andcompressing the archive file when the archive file is stored in anotherstorage device (i.e., the second storage device 30).

As mentioned previously, the data backup device 40 according to thepresent embodiment groups data files to be copied into one archive filebefore the data files are copied, thereby yielding the advantages ofbeing able to reduce the time required to copy the data files to thesecond storage section 30 and being able to significantly improve theprocessing capability of the data backup device 40.

Further, since the data backup device 40 causes the archive filecreation section 102 to create an archive file and the backup processingsection 103 to copy the thus-created archive file in a distributedmanner, the data backup device can speedily and accurately perform theprocessing operations, thus increasing the processing rate of the databackup device 40.

The individual sections provided in the data backup device 40 accordingto the present invention can be used in any combination to itsapplication. For this reason, by virtue of the synergistic effect causedby the characteristics of the individual sections of the data backupdevice, the performance of the data backup device 40 can besignificantly improved.

The present invention is not limited to the foregoing embodiment and maybe modified in various ways without departing the scope of theinvention.

What is claimed is:
 1. A data backup device for use with a computerwhich stores data files stored in a first storage section into a secondstorage section in a duplicate manner, said device comprising: aselection unit selecting, among the data files stored in the firststorage section, a plurality of desired data files satisfying archivesize optimizing conditions; an archive file creation section creating anarchive file comprising said plurality of selected desired data files insaid first storage section; and a backup processing section for storinginto the second storage section said archive file created by saidarchive file creation section.
 2. The data backup device for use with acomputer according to claim 1, wherein said selection section isconfigured to select a data file of a given size or smaller.
 3. The databackup device for use with a computer according to claim 1, wherein saidarchive file creation section is operable to repeat the operation Mtimes, and said selection section is configured in such a way that whensaid archive file creation section is performing the m^(th) operation(where m is a natural number satisfying m≦M and m≧2), said selectionsection selects only those data files which have been modified or newlycreated since said archive file creation section performed the m−1^(th)operation.
 4. The data backup device for use with a computer accordingto claim 1, wherein said archive file creation section is operable torepeat the operation M times, and said selection section is configuredin such a way that when said archive file creation section is performingthe m^(th) operation (where m≦M and m≧2), said selection section selectsonly those data files which have been modified or newly created sincesaid archive file creation section performed the first operation.
 5. Thedata backup device for use with a computer according to claim 1, whereinsaid archive file creation section is configured in such a way that,after having created an archive file, said archive file creation sectioncompresses the thus-created archive file.
 6. The data backup device foruse with a computer according to claim 1, wherein said archive filecreation section is configured in such a way that, after havingcompressed each of data files, said archive creation section createsarchive files.
 7. The data backup device for use with a computeraccording to claim 1, wherein said archive file creation section isoperable to repeat the operation M times, and said archive file creationsection is configured in such a way that said archive file creationsection adds the data file selected by the selection section during themth operation (where m≦M and m≧2) of said archive file creation sectionto the archive files created during the m−1^(th) operation of saidarchive file creation section.
 8. The data backup device for use with acomputer according to claim 1, wherein said archive file creationsection is operable to repeat the operation M times, and said archivefile creation section is configured in such a way that, said archivefile creation section deletes an existing data file corresponding toobject data file to be added to the archive files and then adds the datafiles selected by said selection section during the m^(th) operation(where m≦M and m≧2) of the archive file creation section to the archivefiles created during the m−1^(th) operation of said archive filecreation section.
 9. The data backup device for use with a computeraccording to claim 1, wherein said backup processing section isconfigured to store into the second storage section the archive filesand those data files that have failed to satisfy archiving optimizingconditions.
 10. The data backup device for use with a computer accordingto claim 1, wherein said backup processing section is configured tocompress the archive files and those data files that have failed tosatisfy archiving optimizing conditions and then store thethus-compressed files into the second storage section.
 11. The databackup device for use with a computer according to claim 1, wherein saidbackup processing section is configured in such a way that, after havingadded to the archive files, another archive file or those data filesthat have failed to satisfy archive size optimizing conditions, saidbackup processing section stores the archive files into the secondstorage section.
 12. The data backup device for use with a computeraccording to claim 1, wherein said backup processing section isconfigured in such a way that, after having grouped into another archivefile the archive files and those data files that have failed to satisfygiven conditions, said backup processing section stores the thus-groupedarchive files into the second storage section.
 13. The data backupdevice for use with a computer according to claim 1, wherein said backupprocessing section is configured to cause said archive file creationsection to create an archive file one time immediately before storing tothe second storage section the archive files and those data files thathave failed to satisfy given conditions.
 14. A data backup method foruse with a computer which stores data files stored in a first storagesection into a second storage section in a duplicate manner, the methodcomprising: selecting a plurality of desired data files, which satisfyarchive size optimizing conditions, among the data files stored in thefirst storage section; creating an archive file comprising saidplurality of selected desired data files in said first storage section;and storing said archive file into the second storage section afterrepeating said selecting of the data file and said creating of thearchive file creation at least one time.
 15. A computer-readablerecording medium on which a data backup program is recorded foractivating a computer in order to store data files stored in a firststorage section into a second storage section in a duplicated manner,wherein said program instructs the computer to execute the following:selecting a plurality of desired data files, which satisfy archive sizeoptimizing conditions, in the first storage section; creating an archivefile comprising said plurality of selected desired data files; andstoring the created archive file into the second storage section.